Sewing unit having a stencil rail for guiding the material

ABSTRACT

Sewing unit comprising a stencil bar driven in longitudinal direction having a pressure strip for sewing blanks and a guide bar which continuously is in frictional engagement with a guide means engaged by a support which effects movements superimposed laterally of the longitudinal direction which depend on the form of the guide bar, where a support plate is movable transversely of and independently of the longitudinal movement of the stencil bar.

Mall Ian. l, 1974 SEWING UNIT HAVING A STENCIL RAIL 3,228.364 1 H966 Kremer et al 112/121.11 FOR I G THE MATERIAL 3,448,706 1/1969 Chisholm et a1 l l2/l2l.l2

[75] Inventor: Gunther Mall, Kaiserslautern, FOREIGN PATENTS OR APPLICATIONS Germany 175,445 12/1952 Austria ll2/l2l.l5

[73] Assignee: lFirma Pfafi llndustriemaschinen OTHER PUBLICATIONS gggg Sommer, E. Apparatus for Automatic Quilting of Artiy cles of Material Especially Collars [22] Filed: May 1, 1972 [211 App] NCI 249,398 Primary Examiner.lames R. Boler Attorney-Robert H. Jacob 30 IF A l orergn pp lcatron Priority Data ABSTRACT May 3,1971 Germany G 71 16 976.1

Sewing unlt comprising a stencil bar drlven 1n longitu- 52 us. (:1. 112/121.1s dihal direction having a Pressure Strip for Sewing s1 1111.131 .0051) 21/00 blanks and a guide bar which Continuously is in [58] Field of Search 112/121.15, 121.12, tiohal engagement with a guide means engaged by 1 12/1211 1 12129 2 support which effects movements superimposed laterally of the longitudinal direction which depend on the [56] References Cited form of the guide bar, where a support plate is mov- UNITED STATES PATENTS able transversely of and independently of the longitudinal movement of the stencil bar. l,942,l28 1/1924 Sommer ll2/l2l.l5 3,001,489 9/1961 Bond et al. ll2/12l.l2 3 Claims, 6 Drawing Figures PATENTED 1 4 30 Fig.5

I 49 50 L Ii 1 i L I W *1 i 29 27 28 SEWING UNIT HAVING A STENCIL RAIL FOR GUIDING THE MATERIAL BACKGROUND OF THE INVENTION The invention concerns an auxiliary sewing unit for guiding material that is being sewn. More in particular, the invention is concerned with a sewing unit having a stencil bar driven in longitudinal direction and comprising a pressure strip for the material blanks being sewn and a guiding member which is in constant engagement with a guide means received by a carrier for the purpose of effecting movements corresponding to the form of the guide bar which superimpose the longitudinal movement.

Sewing units of this type serve preferably for forming long, straight or curved seams such as occur, for example, as sleeve or back seams in the dress and jacket or coat production. In view of the seams that are usually long, such sewing units are frequently also referred to as long seam machines.

In order to make it possible that seams extending perpendicularly to one another can be made on long seam machines without varying the position of the work blanks, it is an object of the invention to coordinate the feeding mechanism for the work blank and the sewing machine in such a manner that between the sewing machine and the work blank relative movements are made possible which are directed transversely of the longitudinal direction of feed.

SUMMARY OF THE INVENTION The solution of this problem is provided in that the carrier is movable transversely of. the longitudinal direction of feed by means of a driving device which is independent of the drive for the longitudinal movement of the stencil bar.

Due to the displacement of the guide means that takes place transversely of the longitudinal direction of feed of the stencil bar, the stencil bar that is in force transmitting or positive connection with the guide means and therefore the work blank which is seized by its pressure strip on the blank supporting surface is likewise displaced transversely ofthe longitudinal direction offeed, so that with a long seam machine constructed in this manner it is now possible for the first time on a long seam machine to produce a seam which consists of two partial seams that extend perpendicularly to one another, for example a lock seam on the back portions of a jacket in two operations that immediately succeed one another.

In this connection, it is of particular advantage that the relative movement required for producing the seam that extends transversely of the feed in longitudinal direction, is effected between the work blank and the sewing machine by the displacement of that machine part, namely the guiding means, which as an absolutely stationary scanning means makes possible during the longitudinal movement of the stencil bar the lateral movements of the stencil bar that are superimposed on the longitdunal movement. Based on this concept, it is not necessary to interrupt the force transmitting or positive connection between the stencil bar and the guiding means prior to the start of the transverse movement but, rather, the support that carries the guide means in order to effect this forward movement can be driven directly, for example by a pneumatically operated cylinder.

In accordance with a further progressive proposal of the invention, the support is defined by a plate disposed ahead of the front end of the head of the housing of the sewing machine extending parallel thereto and adapted to the form of this front end which is displaceably dis posed by means of guiding bars extending in a horizontal plane perpendicularly to the feed in the longitudinal direction of the stencil bar.

By arranging the support ahead of the front end of the head of the housing of the sewing machine and to the shape of the support or carrier which is adapted to the shape of this front end, there exists the possibility to allow it to rest directly against the head of the housing in position of its path of movement that is closer to the sewing machine so that in this position it is accommodated in a relatively unobtrusive and spacesaving manner.

It is apparent from the above that the construction in accordance with the invention that can be carried out at low technical expenditure the extent of application or the purpose of use of long seam machines has been increased and enlarged to a great extent, particularly in the production of jackets, especially since it has been shown that the long scam machine constructed in accordance with the invention can be employed not only in the production of the back lock seam, but also advantageously in the forming of the rear arm seams when an open slit has to be worked into the arms.

BRIEF DESCRIPTION OF THE DRAWINGS Further details of the invention will become apparent from the following description of an embodiment illustrated in the drawings which is limited to essential features and in which FIG. 1 is a front view of a sewing unit illustrated in simplified form,

FIG. 2 is a side view of the sewing unit, partly in sec tion, with the supporting plate resting against the head of the sewing machine,

FIG. 3 is a partial sectional side view of the sewing unit with the support plate in the end position removed from the head of the sewing machine,

FIG. 41 is a detail along lines IV-IV in FIG. 2, and

FIG. 5 is a schematic illustration of a jacket back portion having a back closing seam and with the stencil bar disposed thereon.

FIG. 6 shows a simplified schematic diagram illustrating the relationship between the electrical and pneumatic structural elements.

DESCRIPTION OF THE INVENTION The sewing unit shown in the illustrative embodiment comprises a frame 1 on which a table top 2 is secured, the top side of which constitutes the support surface for the work blanks. A sewing machine 41 is disposed upon a small extension 3 of the table top 2. The machine comprises a pedestal or column 5, a housing arm 6 and the head 7 having a front end 8. In the head 7 of the housing, a vertically reciprocable needle 9 is mounted in a conventional manner which for forming stitches cooperates with a catcher that is not illustrated. For driving the machine 4 a motor 10 is provided which is secured to the frame 1 and which is operatively con nected to the sewing machine 4 by means of a drive belt 11.

Below the table top two bars 12, 13 that extend parallel to one another and serve for the longitudinal guidance are secured on which a carriage 16 is slidably mounted which is driven by means of a motor 14 by way of a chian 15. Two bars 17, 18 that extend parallel to one another and serve for transverse guidance are secured to the carriage 16 and on which a support 19 is slidably disposed. The support 19 is thus guided in the manner of a compound or cross slide. U-shaped members 20, 21 which have legs of different lengths are secured to the two ends of the support 19. The short ends of the two arms 20, 21 are connected to the support 19, while the long ends extend parallel to the longitudinal axis of the sewing machine 4 spaced above the table top 2. At the free ends of the arms 20, 21, one each pneumatically operated cylinder 22, 23 is provided. At the piston rods 24, 25 of the two cylinders 22, 23 a stencil bar 26 is releasably secured. This consists of a pressure strip 27 for the work blank 28 and a guide strip 29. The pressure strip 27 is provided in the exemplary embodiment proximate its left end with a projection 30 extending transversely of the direction of the sewing machine 4.

On the outside of the sewing machine 4 a guide rod 33 is slidably mounted on bearings 31, 32 in the housing in the upper part of the housing arm 6. At the forward end of the guide rod 33 a plate 34 is mounted, the shape of which is adapted to the form of the head of the housing 7 of the sewing machine 4 in a manner that the plate 34 registers with the edge of the end side 8 of the housing head 7 except for a laterally extending projection for the guide bar 33. The plate 34 is slidably journalled at its lower end on a guide bar 35 secured in the head 7 of the housing and extending parallel to the movable guide bar 33. The plate 34 is provided at the front end with two bearing projections 36, 37 that are disposed vertically above one another with a space therebetween. A vertically extending support rod 38 is slidably guided in these bearing projections.

The guide means for the stencil bar 26 is disposed on the support rod 38. This consists of a plate 39 secured to the lower end of the support rod 38 and two guide rollers 40, 41 disposed on the plate 39 and each rotatable about a vertical axis. The guide bar 29 of the stencil bar 26 extends intermediate these rollers.

The guide rollers 40, 41 are retained in operating position by means of a pressure spring 43 acting on an adjusting ring 42. The adjusting ring 42 presents a laterally projecting guide lug 44 which is slidably received in a vertical slot 45 of the plate 34 and thereby prevents turning of the support bar 38. The rearward end of the guide bar 33 is connected by way of a connecting member 46 with the piston rod 47 of a double acting cylinder 48 which is secured laterally of the housing arm 6 as shown in FIG. 4.

The two double acting cylinders 22, 23 are connected to a source of air under pressure (not shown) and are controlled together by an electromagnetically operable 4/2 way valve 52 (4 connections/2 circuit positions li E6 the double acting cylinder 48 is controlled by an sqwmaans i aflx3942821 1212) valve (53) which is connected with cylinder 48 by means of a tubular conduit 48.

The motor 14 which serves for driving the carriage 16 is supplied with three phase alternating current (phases R, S, T) while motor and the remaining structural elements are operated in the embodiment for the sake of simplicity and clarity by single phase AC (phases T, Mp).

For connecting the sewing assembly a pedal switch 55 is provided that is arranged in a circuit 56 for the valve 52. Furthermore a relay A is disposed in the circuit 56 which has an operating contact A1 that is connected in parallel with pedal switch 55.

An operating contact of a double pole end switch 58 is located in the circuit 57 for valve 53 which is actuated by means of a cam 59 secured to the piston rod 24. The second operating contact of the end switch 58 is located in the circuit 60 of the motor 10.

A cam 61 is provided on piston rod 47, respectively guide rod 33, which cooperates with a terminal switch 62 that has an operating contact mounted thereon. The terminal switch 62 is located in a circuit 63 in which furthermore the switching magnet of a three pole contactor 64 is located which serves for connecting and disconnecting the motor 14. Also for reversing the direction of motor 14 a three pole contactor 65 is provided by means of which the phase sequence S, T for motor 14 is changed. In the circuit 66 for the switching magnet of the contactor 65 a terminal switch 67 which has a stop contact is provided that is actuated by a cam 68 which is adjustably mounted on the guide bar or rod 29.

In a circuit 69 a terminal switch 70 having an operating contact 70 is arranged, likewise actuated by cam 68 as well as a relay B which has three closed circuit contacts B1, B2, B3 and a front contact B4. B1 is in circuit 56, B2 in 63, B3 in 60 and B4 in circuit 66. Furthermore a relay C is disposed in circuit 66 which has a front contact C1 connected parallel to B4.

The manner of operation of the sewing assembly is as follows:

The work blank 28 to be sewn, for example the back part of a jacket or coat, is laid out on the right side of the table top 2 (FIGS. 1 and 6) below the stencil bar 26 which is raised up by means of the cylinders 22, 23. As soon as the work blank 28 is straightened out the sewing assembly is connected by operating the pedal switch 55.

By operating the pedal switch 55 potential is applied to relay A and thereby its operating contact Al is closed. Simultaneously valve 52 is operated which causes cylinders 22, 23 to be supplied with air under pressure so that they lower the stencil bar 26 onto the work blank 28. As soon as the descending stencil bar 26 frictionally contacts the work blank 28 with its pressure strip 27, the two operating contacts of the terminal switch 58 actuated by cam 59 are closed. Simultaneously the valve 53 is switched over, whereby the cylinders 22, 23 are supplied with compressed air in such a manner that they lower the stencil bar 26 onto the work blank 28. As soon as the descending stencil bar 26 with its pressure strip 27 seizes the work blank 28 with frictional engagement, the two operating contacts of the terminal switch 58 actuated by cam 59 are closed. As a result the valve 53 is simultaneously switched on and motor 10 is connected, which results in plate 34 together with stencil bar 26 and work blank 28 being withdrawn in the direction of the head 7 of the housing and the machine starts to operate. Thus the short seam of the slot 49 is formed along the projection 30 that extends transversely of the longitudinal direction of transport of the stencil bar 26.

As soon as the plate 34 comes to rest against the end 8 of the head 7 of the housing, the cam 61 closes the operating contact of the terminal switch 62. This places a potential on the switch magnet of the switching relay 64 whereupon the switching relay 64 turns on the motor 14. These switching operations occur without any delay in time so that immediately upon completion of the transversely extending seam of the slot 49 the back seam 56 which closely follows and extends longitudinally is formed.

The cam 68 is so disposed upon the guide strip 29 that at the point of time that the rearward edge of the work blank 26 arrives below the needle 9 it actuates the end switch 70 so that potential is placed on the relay B. As a consequence, the closed circuit contacts B1, B2 and B3 are opened and thus the motors 10, M are turned off while the valve 52 is again switched back to the position illustrated in FIG. 6. As a result, the cylinders 22, 23 are energized in such a manner that the stencil bar 26 is raised and thus frees the work blank 28 which has been finished. During the raising of the stencil bar 26, the cam 59 moves away from the terminal switch 58 thus opening its operating contacts. This interrupts the circuit 59, and the valve 53 is switched to the position shown in FIG. 6, whereupon the plate 34 and thus the stencil bar 26 is slid into the position remote from the front end 8 of the head 7 of the housing shown in FIG. 6.

At the same time that the terminal contacts B1, B2, B3 are opened, the operating contact B4 is closed so that the switching magnet of the switching relay 65 is supplied with potential and, as a result, motor 14 for the return movement of the stencil bar 26 is turned on. As a result of the closing of the circuit 66 also relay C is actuated, and thereby its operating contact Cl is closed. As soon as the stencil bar reaches the position shown in FIG. 6, the cam 68 actuates the end switch 67, thereby interrupting the circuit 66 and in this manner turns off the motor 14. Thus, all structural elements have again reached the inoperative or starting position illustrated in MG. 6.

In order to make it possible to influence the speed of advancing the plate 36, it is also possible to employ a combined driving unit. Such a unit consists of a normally connected compressed air cylinder and an added hydraulic cylinder with a closed oil circuit. The piston rod of the compressed air cylinder is connected with the piston rod of the hydraulic cylinder in such a manner that by actuating the compressed air cylinder, the piston of the hydraulic cylinder is constrained to move along.

The feeding velocity may in this connection be influenced by a choke valve built into the oil circuit in that its cross-section for the flow is increased or decreased.

The transverse movement of the plate 39 and the guide rollers 46, ill constituting the guide means may also be realized in a manner different from that in accordance with the illustrated embodiment.

Thus, for example, the guide means may be arranged at the lower end of an essentially vertical lever which is pivotable about a horizontal axis extending parallel to the direction of the longitudinal feed of the stencil bar 26. The cylinder 46 which effects the feed movement in the transverse direction could then directly engage this lever. Since in such an arrangement the lever and the plate 39 assume an oblique position while car rying out a feed movement in transverse direction, the guide rollers 40, 41 must either be arranged for pivotal movement or their surfaces must be of spherical shape.

The shape of the seam 50 of the back is determined by the shape of the guide strip 29 that moves between the guide rollers 46, 41. Since the guide strip 29 of the stencil bar 26 which is used in the embodiment shown is rectilinear, also the back seam 56 formed therewith will extend along a straight line. if, however, the guide strip 29 were arcuately shaped, then also an arcuately shaped back seam 56 would be formed. In that event the stencil bar 26 would with the cylinder 48 at standstill and motor M connected would effect movements directed obliquely to its longitudinal extent, the magnitude and direction of which depend on the guide strip and the longtitudinal movement and which are superimposed to the straight line movement of the stencil bar 26 imparted by the motor 114.

In the event that in a jacket the slot seam does not extend perpendicularly but obliquely with respect to the back seam, such a slot seam can also be produced in that with the start of the transverse movement of the plate 34! simultaneously also the longitudinal feed of the stencil bar 26 is actuated, and in this manner the work blank 28 is moved obliquely relative to the sewing machine 4.

If the slot seam departs only slightly from the perpendicular direction, the longitudinal feed of the stencil bar 26 must then take place at substantially lower speed than its transverse displacement. For this purpose a motor of variable speed could be used. This motor would during the sewing of the slot seam run at correspondingly low speed and upon finishing the slot seam it would automatically be shifted to the higher speed required for the longitudinal feed.

Having now described my invention with reference to the embodiment illustrated in the drawings, what II desire to protect by letters patent is set forth in the appended claims.

ll. Sewing unit for use with a sewing machine having a housing and a machine head, a frame having a table top supporting said machine, a guided shaft extending longitudinally of said housing, a cylinder mounted on the machine and supporting one end of said shaft for movement longitudinally of the machine, a plate secured to the other end of said shaft for supporting guide means and movable with said shaft relative to said machine head, a stencil bar disposed on said table top transversely of said machine head and including a pressure strip for frictional engagement with material blanks below it and a guide strip in constant engagement with said guide means, means operatively related to and extending to the ends of said stencil bar, means for driving said stencil bar in the direction of the longitudinal extent of said stencil bar, said guide means being adapted to effect movements directed laterally of the longitudinal extent of said stencil bar as determined by the shape of the guide strip, said plate and said guide means being movable by said cylinder independently of the longitudinal movement of said stencil bar.

2. Sewing unit in accordance with claim ll, including a further shaft mounted in said machine head below said guided shaft, said plate extending parallel to said machine head, and having bearing projections, and said guide means having a support rod in engagement with said bearing projections.

3. Sewing unit in accordance with claim 2, including a cylinder at each end of said stencil bar for raising said bar to place material blanks thereunder.

=i =l= 1i =1 =2 

1. Sewing unit for use with a sewing machine having a housing and a machine head, a frame having a table top supporting said machine, a guided shaft extending longitudinally of said housinG, a cylinder mounted on the machine and supporting one end of said shaft for movement longitudinally of the machine, a plate secured to the other end of said shaft for supporting guide means and movable with said shaft relative to said machine head, a stencil bar disposed on said table top transversely of said machine head and including a pressure strip for frictional engagement with material blanks below it and a guide strip in constant engagement with said guide means, means operatively related to and extending to the ends of said stencil bar, means for driving said stencil bar in the direction of the longitudinal extent of said stencil bar, said guide means being adapted to effect movements directed laterally of the longitudinal extent of said stencil bar as determined by the shape of the guide strip, said plate and said guide means being movable by said cylinder independently of the longitudinal movement of said stencil bar.
 2. Sewing unit in accordance with claim 1, including a further shaft mounted in said machine head below said guided shaft, said plate extending parallel to said machine head, and having bearing projections, and said guide means having a support rod in engagement with said bearing projections.
 3. Sewing unit in accordance with claim 2, including a cylinder at each end of said stencil bar for raising said bar to place material blanks thereunder. 